Optimizing Query (Index)

Hi,

I have two tables; table1 has 3500 records (small table) and table2
(bigtable) has 25 million records.

I need to Inner Join the two tables based on two columns in each table.

My query reads (I have changed the literal names here for easier
reading):

SELECT sm.recordid, sm.areaid, bg.distance

FROM smalltable sm

INNER JOIN bigtable bg ON (bg.originid=sm.originid AND
bg.detinationid=sm.detinationid)

WHERE sm.somecondition>0

I have tried indexing the originid and destinationid columns in both
tables, and indexed the somecondition column but my query is still
running extraordinarily slow. I looked at the query plan, and it seems
that my query plan only references the index on the somecondition
column. I need to make this run much faster, any tips?

Regards,

B